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Free Converters & Calculators

Unit, currency, age, BMI, loan EMI, percentage, date and time zone calculators. Everything runs in your browser and nothing you enter is recorded.

8 tools planned in this category — none built yet.

These tools handle the small calculations that are easy to get wrong by hand: how old someone is to the day, what a loan actually costs each month, how many days until a deadline, what a measurement is in another unit system.

They are also, quietly, tools you put personal information into — a date of birth, a salary, a loan amount, a body weight. That information is processed in your browser and is never sent to us.

Planned

Scheduled, not yet built. Nothing here links anywhere — no dead ends.

Coming soon

Unit Converter

Convert length, weight, temperature, volume and area between metric and imperial units.

Coming soon

Currency Converter

Convert between world currencies using live exchange rates.

Coming soon

Age Calculator

Work out an exact age in years, months and days from any date of birth.

Coming soon

BMI Calculator

Calculate body mass index and see the matching category, in metric or imperial units.

Coming soon

EMI & Loan Calculator

Find the monthly payment on a loan and read the full amortisation schedule.

Coming soon

Percentage Calculator

Several percentage modes in one place: of a number, increase, decrease and difference.

Coming soon

Date Difference Calculator

Count the days, weeks and months between any two dates.

Coming soon

Time Zone Converter

Convert a time across zones and find a meeting slot that works for everyone.

What these tools cover

Length, weight, temperature, volume and area conversion; live currency rates; exact age from a date of birth; body mass index; loan EMI with a full amortisation schedule; several percentage modes; the gap between two dates; and time zone conversion with a meeting-time finder.

The one exception to "nothing leaves your device"

The currency converter needs today's exchange rates, and rates only exist on a server somewhere. That tool will make one outbound request for rate data and will say so plainly on its page. The request carries no information about you or about the amount you are converting — the conversion itself is still done locally, once the rates arrive. Every other tool in this category makes no network request at all.

Frequently asked questions

Do these calculators need an internet connection?
Only the currency converter, which has to fetch live exchange rates from somewhere. Everything else — unit conversion, age, BMI, loan EMI, percentages, date differences — is arithmetic done in your browser and works offline once the page has loaded.
Is anything I enter recorded?
No. Dates of birth, salaries, loan amounts, weights and heights are all processed locally and never transmitted. There is no account, no history and no server-side log of what you calculated.
How accurate is the age calculator around leap years?
It counts calendar dates rather than dividing by 365.25, so 29 February birthdays and leap years are handled correctly. The result is the same figure an official form would expect: completed years, then completed months, then remaining days.
Will the EMI figure match what my bank quotes?
It will match the standard reducing-balance EMI formula, which is what most lenders use. Real quotes often differ because of processing fees, insurance bundled into the loan, a different day-count convention, or a floating rate. Treat the result as an accurate model of the maths, not as a lender’s offer.
Is a BMI figure medically meaningful?
It is a rough population-level screening number, not a diagnosis. BMI does not distinguish muscle from fat, and it systematically misreads athletes, older adults, and some ethnic groups — several health authorities use different category thresholds for South Asian populations for exactly this reason. Discuss the number with a clinician rather than acting on it alone.
Which unit systems are supported?
Metric and imperial in both directions, including the units that differ between countries — US and UK gallons, US and imperial fluid ounces — since silently mixing those is a common source of wrong answers.

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